import java.util.*;
import java.lang.annotation.*;
import java.lang.ref.*;

class Product {}
class ProductType{}
class Branch {}
class Revision {}

interface AssociationSource<T> {

  Link<T> getTarget();

  void setTarget(Link<T> _target);

}
aspect ExtendProduct {
       Link<T> AssociationSource<T>._target = null;

       public Link<T> AssociationSource<T>.getTarget() {
           return _target;
       }

       public void AssociationSource<T>.setTarget(Link<T> _target) {
         this._target = _target;
       }

       declare parents : ProductType implements AssociationSource<Product>;
/*
       declare parents : Product     implements AssociationSource<Branch>;
       declare parents : Branch      implements AssociationSource<Revision>;
*/
}

class Link<T> {//extends SoftReference {

/*   @SuppressWarnings("unchecked")
   Link(List<T> endPoints) {
       super(endPoints);
   }

   @SuppressWarnings("unchecked")
   public List<T> getEndPoints() {
       return (List<T>)get();
   }
*/

}
